Cryogenic Exfoliation of Non‐layered Magnesium into Two‐Dimensional Crystal

: Physical exfoliation of layered precursors is one of the most prevailing techniques to prepare two-dimensional (2D) crystals, which, however, is considered to be intrinsically inapplicable to non-layered bulks. Now, plane cleavage differentiation is identified in metallic magnesium at cryogenic temperature (CT), and a cryogenic exfoliation strategy of non-layered magnesium into 2D crystals is developed. The cleavage anisotropy of the Mg lattice in response to the external mechanical stress originates from the CT-induced specific inactivation of basal slip, which results in the basal cleavage perpendicular to c axis. The exfoliated novel 2D Mg crystals exhibit remarkable localized surface plasmon resonances, holding great promise for the applications in harvesting and converting solar energy. Beyond creating a new member for the burgeoning 2D family, this study may provide a useful tool for the physical exfoliations of various non-layered materials.